Kansas City Mo. Bus Token?

Here is a Full Fare bus token & the original spring loaded holder. Looks like the holder will hold 5 to 10 tokens. Just press down & pull out a token, or to load more in. Only have one token. The holder says St. Louis Public Service Co. on the bottom. The holder is about 1" tall. Anybody know when bus's came in for transpirtation back in the day? Early 50's maybe? Hmmmmmm, maybe I can get a free ride to St. Louis!!! LoL..... I need a little info on this one!